Sinus ostium

The human nose is the most protruding part of the face. It bears the nostrils and is the first organ of the respiratory system. It is also the principal organ in the olfactory system. The shape of the nose is determined by the nasal bones and the nasal cartilages, including the nasal septum which separates the nostrils and divides the nasal cavity into two. On average the nose of a male is larger than that of a female.Class I. The aquiline nose.Class II. The Grecian nose.Class III. The African nose.Class IV. The hawk nose.Class V. The snub nose.Class VI. The celestial nose. The human nose is the most protruding part of the face. It bears the nostrils and is the first organ of the respiratory system. It is also the principal organ in the olfactory system. The shape of the nose is determined by the nasal bones and the nasal cartilages, including the nasal septum which separates the nostrils and divides the nasal cavity into two. On average the nose of a male is larger than that of a female. The main function of the nose is respiration, and the nasal mucosa lining the nasal cavity and the paranasal sinuses carries out the necessary conditioning of inhaled air by warming and moistening it. Nasal conchae, shell-like bones in the walls of the cavities, play a major part in this process. Filtering of the air by nasal hair in the nostrils prevents large particles from entering the lungs. Sneezing is a reflex to expel unwanted particles from the nose that irritate the mucosal lining. Sneezing can transmit infections, because aerosols are created in which the droplets can harbour pathogens. Another major function of the nose is olfaction, the sense of smell. The area of olfactory epithelium, in the upper nasal cavity, contains specialised olfactory cells responsible for this function. The nose is also involved in the function of speech. Nasal vowels and nasal consonants are produced in the process of nasalisation. The nasal cavity is the third most effective vocal resonator. There are many plastic surgery procedures on the nose, known as rhinoplasties available to correct various structural defects or to change the shape of the nose. Defects may be congenital, result from nasal disorders or from trauma and these are carried out by reconstructive surgery. Procedures used to change a nose shape electively are carried out by cosmetic surgeries. Several bones and nasal cartilages make up the bony-cartilaginous framework of the nose, and the internal structure. The nose is also made up of types of soft tissue such as skin, epithelia, mucous membrane, muscles, nerves, and blood. In the skin there are sebaceous glands, and in the mucous membrane there are nasal glands. The framework of the nose is made up of bone and cartilage which provides strong protection for the internal structures of the nose. The arrangement of the cartilages allows flexibility through muscle control to enable airflow to be modified. The nasal part of the frontal bone lies between the brow ridges, and ends in a serrated nasal notch. The notch articulates at the front with the paired nasal bones, and at the sides with the small lacrimal bones, and with the frontal process of each maxilla. The nasal bones in the upper part of the nose are joined together by the midline internasal suture. They join with the septal cartilage at a junction known as the rhinion. The rhinion is the midpoint of the internasal suture at the join with the cartilage, and from the rhinion to the apex, or tip, the framework is of cartilage. Above and to the back, the bony upper part of the nasal septum is made up of the perpendicular plate of the ethmoid bone, and the bony lower part is made up of the vomer bone that lies below. The floor of the nose is made up of the incisive bone and the horizontal plates of the palatine bones, and this makes up the hard palate of the roof of the mouth. The two horizontal plates join together at the midline and form the posterior nasal spine that gives attachment to the musculus uvulae in the uvula.